According to Bynum's "Marriage Bonds of Tryon and Lincoln Counties, North Carolina", Daniel M. Forney, a grandson of my Forney progenitor, was witness for the marriage between Philip Cline and Elizabeth Abernathy.
I show Philip & Betsy Cline couple had 11 children. I've not followed them as extensively nor as assidiously as I've followed various other Abernathy lines, but I believe that you must descend from the marriage of grandaughter Emily Elizabeth Mayfield who married Lycurgus Carl Brown.Does your family have any knowledge of the Letty Abernathy who is found with one of Nathan's grandsons on the 1860 Cherokee County GA census?
To the best of my knowledge at this time, I cannot verify that Nathan's line (which has been traditionally cited as one of the descendant branches of the Lineage of the first Robert Abernathy of Virginia to which my ancestor David Abernathy Sr of Lincoln Co, NC belonged) is, in fact, related to the first Robert after all. Present evidence suggests instead that it may be more closely related to some of the Scots-Irish Abernethys. Additional testing is presently in progress to confirm or refute this, so any evidence you may have of direct male descendants of Nathan or his brother Seth might be of assistance. Alas, Elizabeth (Abernathy) Cline's descendants are excluded due to the nature of the tests.